Return to Chemistry IndexMole Relations

Samuel E. Hall, Jr. Chgo H. S. for Ag. Sciences

3807 W. 111th Street

Chicago, Illinois 60655

312-881-5000Objectives:

Grade level: Sophomore chemistry

Students should be able to: (a) define the "mole"; (b) state the mole

relationship between components of a chemical equation.Apparatus Needed:

Per team of 3 students:

30 Raisins

40 Sunflower seeds (purchase a jar of the meat of sunflower seeds)

30 M & M candy

2-3 Napkins

12 Sandwich bags

Transparencies and overhead projector or chalkboard. Soap and towels for

washing hands. Set of "blackline" copies of transparencies will be sent upon

request. You can make the transparencies from these copies.Recommended Strategy:Start by having the class form groups of three. Tell the group that you need help in making some packages of trail mix. Trail mix is a kind of nutrient mix used to munch on while hiking or bicycling and the like. Our trail mix is skimpy for reasons of teaching the concept of "mole". Give each team a recipe and an abundance of each of the three items (raisins, sunflower seeds, and m & m's). The group of students should count the ingredients and actually make the number of trail mix packages called for in the recipe. The students should count 1 dozen raisins, 3 dozen sunflower seeds, and 2 dozen m & m's. With this stock, the group is instructed to make 1 dozen trail mix packages. The actual number of each ingredient in each package of trail mix. PROJECT ON OVERHEAD: 1 dozen 3 dozen 2 dozen 1 dozen raisins + sunflower + m & m's + trail mix seeds packages Continuing, groups should calculate that each of 12 trail mix packages contains 1 raisin, 3 sunflower seeds and 2 m & m's. Next, ask students to calculate the number of ingredients necessary to make 1.5 dozen trail mix packages. Third step: Ask students if you can abbreviate some names used in writing the recipe. PROJECT ON OVERHEAD: 2 dozen 3 dozen 2 dozen 1 dozen R + SS + MM -------> TM Where R = raisin; SS = sunflower seed; MM = m & m candy; TM = trail mix package. Ask the teams to determine the amount of each item to be placed in the trail mix packages. It is important that answers be expressed in DOZENS not units. In discussion attempt to have all teams understand how to calculate the number of dozen(s) of each ingredient needed. PROJECT ON OVERHEAD: 3 R + 3 SS + 2 MM ----> 1 TM Ask student if you can write a recipe without writing the word "dozen" because you are getting tired or writing "dozen" so many times. After students are comfortable with the above relationships, introduce the term "mole". The concept of dozen is similar to the concept of mole. Define dozen and define mole. Tell the students that one dozen of anything contains 12 items and one mole of anything contains 6 x 10^{23}items. Now re-write the trail mix recipe

substituting mole for dozen. Write and discuss other examples of chemical

equations to give practice in mole relationships.